Study for the evaluation of the natural origin of the presence of iron and manganese in groundwater. Site of national interest 'Lower Basin Chienti River'

The hydrological balance of the basin is used to give an estimate of the volumes of water exchanged between inflows and outflows. It takes into account parameters such as:
- global water runoff: sum of the volumes of water runoff at the surface (which will, in turn, feed into groundwater) and of effective infiltration (which flow out from the aquifer to delivery points such as rivers, springs, lakes and sea).
- rainfall water.
- actual evapotranspiration: the volume of water coming out of the ground by evaporation corrected by factors such as: the evaporating power of the atmosphere, the average annual temperature and the average monthly rainfall.
The calculation takes into account the period 1950-1989 (F.Pallotta et al.) and provides us with the values of the mean monthly actual rainfalls (i.e. corrected by the factors mentioned above) and the water flow of the individual areas. The outflow has greater discharge in the areas located at higher altitudes (with higher potential energy) and lower in those near the coast. This gives us a temporal and geographical information. The temporal one is needed to understand the seasonal variations in the volumes of water involved, taking into account the fact that samplings were carried out in July-August, the geographical one allows us to relate to the different piezometers the extent of the renewal of the groundwater and therefore its possible dilution.